This invention relates to processes for embossing machine-readable information onto a document. The information may be for indicating the genuineness of the document. The invention also relates to documents so embossed.
Documents such as indentity cards, credentials, tickets, securities and the like have become an indispensable aid to everyday life. The monetary or legal value of such documents is often considerable, which induces the criminal elements of society to forge, change or copy such documents.
In the industrialized countries, machines are being increasingly used to test the genuineness or identity of documents. Examples are devices for checking securities, credit card reading devices and admission or travel ticket acceptance devices. If the genuineness or identity features of documents to be checked by machines are made too simple, this again constitutes an inducement to fraudulent dealings.
Identity cards are known which are protected against forgery by a refracting shape being stamped into a plastic support member. Furthermore, it has already been proposed to emboss machine-readable information indicating genuineness in the form of optical markings onto a plastic means of payment, which markings have a light-modifying relief structure and can be holograms, kinoforms, miniature Fresnel prisms and the like.
The problem of the present invention is to provide a process of the type indicated hereinbefore by means of which very fine optical markings can be applied to documents which are made from a material which, due to its fibrous, granular or cellular structure, is in itself unsuitable for receiving the desired characteristic relief structure.
According to the present invention there is provided a process for embossing machine-readable information for indicating genuineness onto a document, in the form of optical markings with a light-modifying relief structure, wherein a thermoplastic layer is transferred to the document from an embossing foil by a hot embossing die and simultaneously the optical markings are embossed both in the thermoplastic layer and in the document.